The present invention relates to a steel-making arc furnace whose capacity is variable.
A conventional arc furnace has a predetermined furnace capacity. Therefore, in the case of overcharging the charge (scrap), the overcharged charge is pressed by means of a charging bucket or an operator must climb over the top of the furnace so as to collapse and smooth the pile of the charge. Furthermore, if the arc furnace cannot be filled by one charging, the charge must be charged into the furnace many times.
Since the conventional arc furnaces have a predetermined furnace capacity, there arises the problem that even when the charge is melted and the pile of the charge is lowered, the furnace capacity cannot be varied so that not only the unneeded thermal losses but also electrode consumption due to oxidation and resulting wear of electrodes in the furnace are increased.
In view of the above, according to the present invention, a furnace capacity is made variable so that the charge can be overcharged in a simple manner. Furthermore, when the pile of the charge is lowered, the furnace capacity is decreased so that unneeded thermal losses and oxidation and resulting wear of electrodes can be reduced to a minimum.